What would we do next, given more time?

Discuss connections with other ecosystem indicators in the SOE

The following figures and text are from the most recent (2021) Mid-Atlantic State of the Ecosystem report.

# Image Directory
image.dir <- here::here("docs/images")
gis.dir <- here::here("data-raw/gis")
#Default Rmd options
knitr::opts_chunk$set(echo = FALSE,
                      message = FALSE,
                      warning = FALSE,
                      fig.align = 'center') #allows for inserting R code into captions

#Plotting and data libraries
library(ggplot2)
library(dplyr)
library(tidyr)
library(ecodata)
library(here)
library(kableExtra)
library(ggrepel)
library(stringr)
#library(patchwork)
library(grid)
library(cowplot)

#GIS libraries
library(sf)
library(rgdal)
library(raster)
library(ggspatial)
library(marmap)


#General inline text input for report

#Council
council <- "Mid-Atlantic Fishery Management Council"
council_abbr <- "MAFMC"

#Region identifiers
epu <- "Mid-Atlantic Bight"
epu_abbr <- "MAB"
region <- "Mid-Atlantic"
region_abbr <- "MA" #Some commercial data organized by "MA" or "NE" regions, not by EPU 
  • Climate is trending into uncharted territory. Globally, 2020 was tied with the warmest year on record1.

Water temperature is warming

Ocean temperatures continue to warm at both the bottom and the surface. Warming is not seasonally uniform, however: spring 2020 was cooler than average on portions of the shelf.
Annual bottom temperature in the Mid-Atlantic Bight. (black = in situ observations, red = observations assimilated by ocean model for comparison)

Annual bottom temperature in the Mid-Atlantic Bight. (black = in situ observations, red = observations assimilated by ocean model for comparison)

MAB seasonal sea surface temperature (SST) time series overlaid onto 2020 seasonal spatial anomalies.

MAB seasonal sea surface temperature (SST) time series overlaid onto 2020 seasonal spatial anomalies.

Species ranges are shifting

Fish stocks are shifting distribution, moving towards the northeast and into deeper waters throughout the Northeast US Large Marine Ecosystem.

Aggregate species distribution metrics for species in the Northeast Large Marine Ecosystem.

Aggregate species distribution metrics for species in the Northeast Large Marine Ecosystem.

Energy content of some forage fish is changing

Nutritional value (energy content) of juvenile and adult forage fishes as prey is related to both environmental conditions, fish growth and reproductive cycles. Forage energy density measurements from NEFSC trawl surveys 2017-2019 are building toward a time series to evaluate trends. New 2019 measurements were consistent with last year’s report: the energy density of Atlantic herring was almost half the value (5.69 +/- 0.07 kJ/g wet weight) reported in earlier studies (10.6-9.4 kJ/ g wet weight). Silver hake, sandlance, longfin squid (Loligo below) and shortfin squid (Illex below) were also lower than previous estimates (Steimle and Terranova 1985; Lawson, Magalhães, and Miller 1998). Energy density of alewife, butterfish and Atlantic mackerel varies seasonally, with seasonal estimates both higher and lower than estimates from previous decades.

Forage fish mean energy density mean and standard deviation by season and year, compared with 1980s (Steimle and Terranove 1985) and 1990s (Lawson et al. 1998) values.

Forage fish mean energy density mean and standard deviation by season and year, compared with 1980s (Steimle and Terranove 1985) and 1990s (Lawson et al. 1998) values.

Next steps for diet analysis

Examine the individual prey categories: are any particular fish prey driving the increase in the MAB in Fall? are any particular benthic invertebrates disappearing from diets in the MAB in Fall?

References

Lawson, John W., Alexandra M. Magalhães, and Edward H. Miller. 1998. “Important Prey Species of Marine Vertebrate Predators in the Northwest Atlantic: Proximate Composition and Energy Density.” Marine Ecology Progress Series 164: 13–20. https://www.jstor.org/stable/24825521.
Steimle, Frank, and Russell Terranova. 1985. “Energy Equivalents of Marine Organisms from the Continental Shelf of the Temperate Northwest Atlantic.” Journal of Northwest Atlantic Fishery Science 6 (December). https://doi.org/10.2960/J.v6.a11.

  1. https://www.nasa.gov/press-release/2020-tied-for-warmest-year-on-record-nasa-analysis-shows↩︎